Modern computer systems place high importance on system security. In many computer systems, and especially those involving virtualized computing environments where a plurality of guest virtual machines may be hosted on shared physical host machines, security of data within a virtual machine instance or between host machine instances may become a concern. An application running within a virtual machine instance may selectively protect secrets from code running on other virtual machine instances on the same host machine and may also selectively protect secrets from code running on the same virtual machine instance. In some implementations a physical hardware module or a virtualized version of the same may exist to help facilitate protecting secrets but such implementations may require integration with host machine operating systems, virtual machine operating systems and/or controlling domains. Both physical and virtual implementations may also suffer from limited access to the shared module resource. Because, in many implementations, a single host system supports multiple guest operating systems, and because a single computing environment may have many host systems, service access limitations can adversely affect a large number of guest virtual machines. Additionally, as system complexity increases over time, so too does the need for better security solutions.